When a rolling tire is caused to vibrate by irregularities on a road surface, the vibration is transmitted to the vehicle cabin through suspensions, and further vibrates the ceiling, floor, and the like of the vehicle cabin. A resonance sound generated by resonance of air inside the vehicle cabin due to the vibration is referred to as road noise.
A conventional pneumatic tire is disclosed in Japanese patent application Kokai publication No. 2004-90766. Specifically, to a shoulder section of a tread of a pneumatic tire mounted on a wheel, at which the vibration transmission ratio to an axle side is largest, many small holes are arranged in the circumferential direction of the tire. The many small holes reduce the stiffness of a tread rubber to thereby improve the vibration absorption performance of the tire so that the road noise can be reduced. However, since small stones and the like on a road surface are likely to be retained in the many small holes provided to the tread during driving, there is a problem that when the small holes are clogged with such small stones, the tread surface is damaged, and hence the durability of the tire is deteriorated.